JPH10198994A - Optical pickup having control mechanism for optical axis of light source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minaturize an optical pick-up by fixing a lens frame and a lens holder with an adhesive after adjusting the lens frame in a direction, in which the optical axis of a lens is inclined with respect to the lens holder, to simplify the device, and also to reduce the number of components. SOLUTION: A lens holder 14 is fixed by holding protrusions 46 formed on the upper surface and the bottom surface of the holder with a jig 45 in a state in which a lens frame 13 is not engaged in the holder. Next, the projecting sphericality 43 of the frame 13 to which a lens 12 is proviously fixed with an adhesive is placed on the recessing sphericality 44 of the holder. In this step, the optical axis A of the lens 12 does not coincide with a desired optical axis 0. Then, the axis A is made to coincide with the axis 0 by rotating the lens frame 13 in this state. When the axis A and the axis 0 coincide with each other, after the lens frame 13 is fixed to the lens holder 14 with adhesive, the adjusting of optical axis of the lens 12 is completed by detaching the jig 45.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens optical axis adjusting device for an optical pickup for reading information recorded on a medium recording medium or writing information on a recording medium.

[0002]

2. Description of the Related Art A conventional lens optical axis adjusting device for optical pickup is described in, for example, Japanese Patent Application Laid-Open No. 59-223954. 2 (a) and 2 (b) are an exploded perspective view and a partial cross-sectional view, respectively, of the above-mentioned prior art. 1
Is an objective lens, 2 is an objective lens driving device for holding the objective lens, 3 is an optical block, 10 is a convex spherical surface formed on the base of the base of the objective lens driving device 2, and 11 is formed or fixed on the upper surface of the optical block. Concave sphere, 4a, 4
b, 4c, 4d are coil springs, 5a, 5b, 5c, 5d
Is a screw hole, and 6a, 6b, 6c and 6d are screws. The convex spherical surface 10 is fitted to the concave spherical surface, and the objective lens driving device 2 is attached to the optical block 3 so as to be rotatable about the centers of the balls 10 and 11. Coil springs 4c, 4
d is compressed by screws 6c and 6d screwed into the screw holes 5c and 5d, and pulls the objective lens driving device 2 toward the optical block 3 with a constant force. Coil springs 4a, 4
b pushes up the objective lens driving device 2 at a constant pressure.

The optical axis of the objective lens 1 is adjusted by a screw 6
This is performed by turning a and 6b.

[0004]

However, in the lens optical axis adjusting device of the above-described optical big-up type, since the structure is such that the entire actuator is displaced, the device becomes large and the number of parts such as screws and springs also increases. There was a disadvantage.

It is an object of the present invention to provide a lens optical axis adjusting device for an optical pickup which eliminates the above-mentioned disadvantages.

[0006]

According to the first aspect of the present invention, there is provided an optical pickup optical axis adjusting device for converging a light beam from a light source on a recording medium on which information is recorded in a track shape by a lens, and An image of the image is formed on a photodetector, and a lens frame for holding the lens in a lens optical axis adjustment device of an optical pickup that reads information on the recording medium;
A lens holder for fixing the lens frame, and a spherical surface provided on a contact surface between at least one of the lens frame and the lens holder, the other being provided with a lens. After performing an adjusting operation in a direction to incline the optical axis, the lens frame and the lens holder are fixed with an adhesive.

According to a second aspect of the present invention, in addition to the optical pickup optical axis adjusting device of the first aspect of the present invention, the lens holder is provided with a portion fixed by a jig to fix the lens holder. The optical axis of the lens is adjusted by tilting the lens frame in the state.

[0008]

An embodiment of the present invention will be described below with reference to the drawings. 1A and 1B are a top view and a side view, respectively, of an optical pickup provided with a lens optical axis adjusting device according to the present invention. The lens 12 to be adjusted according to the present invention is fixed to a lens frame 13, and the lens frame 13 is fixed to a lens holder 14 with an adhesive or the like.

FIG. 3 is an enlarged view of the lens holder 14. As shown in FIG. 14-1 is a reinforcing portion of the lens holder 14, and two penetrating spaces 14-2 sandwiching the reinforcing portion 14-1.
Are formed. In this space 14-2, four grooves 14-3 to which a tracking coil described later is fixed are formed. A groove 14-4 is formed in the side surface of the lens holder 14 to be wound and fixed with a force coil, which will also be described later.

Returning to FIG. 1, four projections 14-5 are formed on the side surface of the lens holder 14, and each projection 1-5 is formed.
One end of each of four elastic wires 16 for movably supporting the lens holder 14 with respect to the base 15 is fixed to 4-5.

On the other hand, the other end of each elastic wire 16 is fixed to a substrate 18 mounted on a base 15 via a rubber member 17 for absorbing resonance. In each of the two spaces 14-2 of the lens holder 14, two tracking coils 19 wound in a rectangular shape are fixed with an adhesive or the like while fitted in the grooves 14-3. On the other hand, a focus coil 20 is wound around a groove 14-4 formed on the side surface of the lens holder 14.

Four permanent magnets 21 are arranged via an air gap so as to face the tracking coil 19 and the focus coil 20. 22.

Similarly, two inner yokes 23 installed on the base 15 are provided in two spaces 1 of the lens holder 14, respectively.
In 4-2, each member of the lens holder 14 and the tracking coil 19 is arranged via a gap. The inner yoke 23 and the outer yoke 22 are integrally fixed by screws 37 shown in FIG. 4, and the permanent magnet 21, the inner yoke 23, and the outer yoke 22 form four magnetic circuits.

Next, the optical system will be described. Reference numeral 24 denotes a reading laser which is disposed slightly shifted from the focal position of the collimator lens 25 in the lens optical axis direction. Reading laser 2
The divergent light beam emitted from 4 becomes parallel light east by the collimator lens 25, and thereafter enters the diffusion plate 26. The diffusing plate 26 is for making the point light source a surface light source.

After passing through the half mirror 27, the light beam 40 emitted from the diffusion plate 26 is bent by 90 degrees by the half prism 28 and then reflected by the right-angle prism 29 to be reflected by the lens 1.
2 is incident. The lens 12 converges a laser beam on a laser card 30 on which information is recorded in a track shape. The reflected light from the laser card 30 follows the original optical path, passes through the half prism 28, and then enters the condensing lens 31.
To the photodetector 32 composed of a photodiode,
An image on the laser card 30 is formed. Half mirror 2
FIG. 5 (a) is an enlarged view of FIG. 7 viewed from the reading laser 24 side.
It is. The half mirror 27 is formed with a light shielding portion 33 so as to sandwich the half mirror 27 from both sides, and the half mirror 27 is connected to the base 15 and the bimorph 34. On the other hand, FIG. 5 (b) is a diagram showing the back side of FIG. 5 (a). On the wheat surface of the bimorph 34, two electrodes 35-
1, 35-2 are fixed, and an electrode 35-3 is fixed on the back side. In addition, a total reflection mirror 38 'is disposed on the back side of the light shielding portion 33 in FIG.

On the other hand, the light beam emitted from the writing laser 38 is converted into a parallel light beam 41 by the collimator lens 39, and thereafter, the optical axis of the half mirror 27 and the total reflection mirror 38 'is substantially 9
Folded 0 degrees. Total reflection mirrors 38 ′ arranged on both sides of the half mirror 27 are for preventing a loss of the amount of light emitted from the writing laser 38.

The half mirror 27 and the total reflection mirror 3
The light beam reflected by the laser card 8 'follows the same optical path as the optical path emitted from the reading laser 24 described above.
0, and the desired recording is performed.

Next, the tracking drive, the focusing drive, and the adjustment of the movement of the beam spot will be described.
When a control current corresponding to the tracking error signal is supplied to the tracking coil 19, the lens 12 moves in the X direction, and tracking driving is performed. When a control current corresponding to the focus error signal is supplied to the focus coil 20, the lens 12 moves in the Y direction and focus movement is performed.

When the focus signal is detected, two rectangular projections 42 are provided on the light shielding portion 33 in order to improve the detection sensitivity.
To reduce the effect of diffraction. In this optical pickup, since reading and writing are performed by the reading laser 24 and the writing laser 38, it is necessary to maintain a predetermined interval between both beam spots on the laser card 30. For this purpose, a voltage is applied between the two electrodes 35-1 and 35-3 and between the electrodes 35-2 and 35-3. When a different voltage is applied between the two electrodes, the bimorph 34 is twisted according to the voltage difference, and the half mirror 27 and the total reflection mirror 33 are tilted accordingly. As a result, the writing beam spot on the laser card 30 is displaced substantially in the Z direction. On the other hand, if the same voltage is applied, the bimorph 34 is deformed without twist, and the writing beam spot is displaced in the X direction.

Next, the adjustment of the optical axis of the lens 12 will be described. FIG. 6A is a partial sectional view showing a state where the lens 12 is fixed to the lens holder 14. A convex spherical surface 43 is formed on the outer surface of the lens frame 13. On the other hand, lens holder 1
4 has a concave spherical surface 44 corresponding to the convex spherical surface 43. As a result, the lens frame 13 can freely rotate around a predetermined reference optical axis O (see FIG. 7) of the optical pickup. The lens holder 14 and the lens frame 13 are joined with an adhesive 47.

FIG. 6 (b) shows a case where the lens frame 13 is supported by corners 48 instead of the concave spherical surface 44 of the lens holder 14 of FIG. 6 (a). In this case, the corner 48 is chamfered to prevent the lens frame 13 from biting. Such a groove structure has an advantage that the structure is simpler than that of FIG. 6 (a). FIG. 6C shows the lens frame 13 having a cylindrical shape except for the concave spherical surface 44 on the side of the lens holder 14 shown in FIG. 6A, and the concave spherical surface 49 is formed at the bottom corner 49 of the chamfered lens frame 13. It is intended to be in contact with.

Next, the procedure for adjusting the optical axis of the lens 12 will be described. First, the lens frame 13 is still in the lens holder 1
4 (but all other members such as the elastic wire 16 are fixed to the lens holder 14)
The lens holder 14 is fixed at a predetermined position. This fixing is performed by sandwiching two projections 46 formed on the upper surface and the bottom surface of the lens holder 14 with a jig 45 as shown in FIG. FIG. 7 (a) uses the structure of the lens frame and lens holder of FIG. 6 (a). Next, the convex spherical surface 43 of the lens frame 13 to which the lens 12 is fixed in advance with an adhesive or the like is placed on the concave spherical surface 44 of the lens holder 14. At this stage, the optical axis A of the lens 12 is
Does not match. Then, the lens frame 13 is rotated to make the axis A coincide with the axis O. When the axis A coincides with the axis O, the lens frame 13 is attached to the lens holder 14 with the adhesive 47 in that state.
To be fixed. Then remove the jig 45 and remove the lens 12
The optical axis adjustment of is completed. FIG. 7 (b) is FIG. 7 (a)
The relationship between the unevenness of the contact portion between the jig 45 and the projection 46 is reversed.

[0023]

According to the present invention, the optical axis of the lens can be adjusted with a simple structure of the mounting surface of the lens frame and the lens holder.
This has the advantage that the device is significantly simplified and the device is smaller.

[Brief description of the drawings]

FIG. 1 is an overall view of an optical pickup provided with a lens optical axis adjusting device of the present invention.

FIG. 2 is a diagram showing a conventional lens optical axis adjusting device.

FIG. 3 is an overall perspective view for explaining a lens holder 14 of the present invention.

FIG. 4 is a perspective view showing an interrelationship between an electromagnetic drive unit of the lens 12 and an optical system.

FIG. 5 is a diagram of an apparatus for moving a beam spot by bimorph.

FIG. 6 shows a lens holder 1 for adjusting the optical axis of the lens 12.
FIG. 4 is a view for explaining a mode in which the fixing member 4 is fixed.

FIG. 7 is a view showing an aspect in which the lens holder is fixed by a jig 45;

[Explanation of symbols]

 Reference Signs List 12 lens 13 lens frame 14 lens holder 16 elastic wire 19 tracking coil 20 focus coil 21 permanent magnet 22 outer yoke 23 inner yoke 24 reading laser 30 laser card 32 photodetector 38 writing laser 43 convex spherical surface 44 concave spherical surface 45 Jig 47 Adhesive

[Procedure amendment]

[Submission date] December 17, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Name of invention

[Correction method] Change

[Correction contents]

Patent application title: Optical pickup having light source optical axis control mechanism
Up

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction contents]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup having a light source optical axis control mechanism for reading information recorded on a recording medium or writing information on a recording medium.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0002

[Correction method] Change

[Correction contents]

[0002]

2. Description of the Related Art A conventional optical pickup is disclosed in
This is described in JP-A-59-58635. Fig. 2
1 is a cross-sectional view of the related art. 1 is medium, 2 is spun
, 3 is an objective lens, 4 is a dichroic mirror, 5 is
Polarization beam splitter, 6 is a semiconductor element, 7 is a coupling
The lens 8 is a differential light detector.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

The laser beam for recording on the medium 1 has an arrow A
Output from one direction, reflected by dichroic mirror 4
Then, the recording surface 1A is irradiated through the objective lens 3, and the recording is performed.
Done. On the other hand, the focus control output from the semiconductor element 6
The light for the coupling is as shown by the arrow B1.
7, the beam is formed into a light beam of a predetermined beam system.
Musplitter 5, dichroic mirror 4 and objective lens
Recording surface via a portion of the lens 3 that is off the center CC
Irradiate 1A.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004]

THE INVENTION Problems to be Solved] However, as described above, such machine
The optical axis of light from each light source is set at the time of manufacturing the device.
Generated due to temperature changes in the environment in which the equipment is used.
The relative position of the beam spot by each light source on the recording medium
Recording and / or playback
Error was easy to occur.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction contents]

[0005] The present onset Ming source light axis adjustment removing the above mentioned disadvantages
An object of the present invention is to provide an optical pickup having a mechanism .

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

[0006]

The light according to the first aspect of the present invention.
An optical pickup with a source optical axis control mechanism
The light flux from the light source is focused on the recording medium
Writing information on the recording medium, and / or
Optical pickup for reading information recorded on the recording medium
A plurality of light sources, and reflecting a light flux from the light sources.
To the mirror, and a light beam reflected by the mirror to the mirror.
Driver that tilts the mirror so that the incident angle of the mirror changes
With steps and

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007] The light beam reflected by the mirror,
Reaches the recording medium without being reflected by the mirror
Of the beam spot on the recording medium with respect to the emitted light flux
Is controlled by tilting the mirror by the driving means.
It is characterized by controlling.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008]

An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 (a) and 1 (b) show the optical axis of the light source of the present invention, respectively.
It is the figure which looked at the optical pickup which has a control mechanism from the upper surface, and the figure seen from the side surface. Lenses 12 is fixed to the lens frame 13 is fixed further the lens frame 13 in the lens holder 14 with an adhesive or the like.

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

Next, the tracking drive, the focusing drive, and the movement adjustment of the beam spot to be controlled by the light source optical axis of the present invention will be described. When a control signal corresponding to the tracking error signal is supplied to the tracking coil 19, the lens 12 moves in the X direction and the tracking drive is performed. When a control current corresponding to the focus error signal is supplied to the focus coil 20, the lens 12 moves in the Y direction and focus driving is performed.

[Procedure amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

When the focus signal is detected, two rectangular projections 42 are provided on the light shielding portion 33 in order to improve the detection sensitivity.
To reduce the effect of diffraction. In this optical beakup, since the reading and writing are performed by the reading laser 24 and the writing laser 38, the light axis adjustment of the light source which is the object of the present invention
It is necessary to maintain a predetermined interval between the two beam spots on the laser card 30 by a mechanism . For this purpose, the electrode 35-1 and the electrode 35-3, the electrode 35-2 and the electrode 35
-3 to apply a voltage between the two electrodes. When a different voltage is applied between the two electrodes , the bimorph 34 as a driving means is twisted according to the voltage difference, and the half mirror 27 and the total reflection mirror 33 are tilted accordingly. As a result, the writing beam spot on the laser card 30 is displaced substantially in the Z direction. On the other hand, if the same voltage is applied, the bimorph 34 is deformed without twist, and the writing beam spot is displaced in the X direction.

[Procedure amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

[0023]

According to the present invention, the beam spot on the recording medium is
The mirror is tilted by the driving means to set the relative distance between the pots.
Beam spot spacing
To control recording and / or playback errors.
Can be prevented.

[Procedure amendment 14]

[Document name to be amended] Statement

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG. 1 is an overall view of an optical pickup having a light source optical axis control mechanism of the present invention.

[Procedure amendment 15]

[Document name to be amended] Statement

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2 is a diagram showing a conventional optical pickup .

[Procedure amendment 16]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

Claims (1)

[Claims] An optical pickup that focuses a light beam from a light source on a track-shaped recording medium by a lens, writes information on the recording medium, and / or reads information recorded on the recording medium. A light source, a mirror that reflects a light beam from at least one of the light sources, and a driving unit that inclines the mirror so that an incident angle of the light beam reflected by the mirror on the mirror changes. An optical pickup for adjusting an interval between a beam spot of the reflected light beam on the recording medium and a beam spot on the recording medium by another light source by tilting the mirror by the driving unit; .